Apparatus for and method of determining oxygen and carbon dioxide in sealed containers

ABSTRACT

An apparatus and a method by means of which oxygen and carbon dioxide dissolved in a liquid in a sealed container and oxygen in the headspace of the same container can be determined. The apparatus can also be used to measure dissolved oxygen in liquids in open containers. A valve fitted with a syringe makes it possible to draw representative samples of known volume from both the headspace and the liquid within the container. The specimens thus obtained are directed into an oxygen-free stream of inert gas from which CO2 is absorbed and the O2 is transferred to an oxygen detector. Dissolved CO2 is determined from a reading of the total gas pressure on a gauge and from measurements of the volume of liquid in the container and the volume of the container itself.

United States Patent [19 1 Garza et al.

APPARATUS FOR AND METHOD OF DETERMINING OXYGEN AND CARBON DIOXIDE INSEALED CONTAINERS Inventors: Adan C. Garza, Avon; Vincent S.

Bavisotto, Simsbury, both of Conn.

Assignee: Brewers Unlimited, Inc., St. Paul,

Minn.

Filed: Sept. 25, 1972 Appl. No.: 292,020

U.S. Cl. 23/230 R, 23/232 R, 23/253 R, 23/254 R, 73/42l.5 R, 73/423 AInt. Cl G0ln 1/16, GOln l/26, GOln 33/14 Field of Search 23/230 R, 253R, 232 R, 23/232 E, 254 R, 254 E, 259, 255 E;

73/42l.5 R, 423 A References Cited UNITED STATES PATENTS Day et al73/421.5 R Stutler et al 23/232 R UX Ashmead 23/254 R X Nov. 19, 19743,374,678 3/1968 McGuckin 73/42l.5 R 3,550,453 12/1970 Lightner et al.73/423 A Primary Examiner-Robert M, Reese Attorney, Agent, or Firm-Blum,Moscovitz, Friedman & Kaplan [5 7] ABSTRACT An apparatus and a method bymeans of which oxygen and carbon dioxide dissolved in a liquid in asealed container and oxygen in the headspace of the same container canbe determined. The apparatus can also be used to measure dissolvedoxygen in liquids in open containers. A valve fitted with a syringemakes it possible to draw representative samples of known volume fromboth the headspace and the liquid within the container. The specimensthus obtained are directed 7 into an oxygen-free stream of inert gasfrom which CO is absorbed and the O is transferred to an oxygendetector. Dissolved CO is determined from a reading of the total gaspressure on a gauge and from measure ments of the volume of liquid inthe container and the volume of the container itself.

9 Claims, 5 Drawing Figures pmzcm WWW 3.849.070

smanr 0X YGE/V m/tm qfaws) 1 APPARATUS FOR AND METHOD OF DETERMININGOXYGEN AND CARBON DIOXIDE IN SEALED CONTAINERS BACKGROUND OF THEINVENTION To date, the determination of CO content or the dissolvedoxygen or headspace oxygen in packaged products is not a routinepractice. Also, the determination of O dissolved in liquids in opencontainers is generally not a routine practice in the brewing industry.Following are examples of products which could benefit from suchdetermination:

brewery wort, non-alcoholic beverages (carbonated and non-carbonated),wines (carbonated and noncarbonated), cocktails, cordials, products inflexible packages, any food or beverage product where oxygen andpossibly carbon dioxide is of importance, any non-food product wheredissolved oxygen or headspace oxygen is important; for example,pharmaceutical products, aerosol products. Occasionally, thismeasurement is accomplished in beer by gasometric or colorimetricmethods. The colorimetric method is accurate to approximately 0.1 ppmbut it is only applicable to the liquid phase and not to the headspace.In addition, the procedure is long and tedious and requires considerableskill on the part of the analyst.

For determination of oxygen in the headspace of a sealed container, theonly methods available are gasometric. These methods, in addition tobeing lengthy and tedious, suffer in sensitivity and at best give onlyan approximation of the oxygen content. The brewing industry has beenparticularly concerned with the problem of dissolved oxygen and oxygenin the headspace of sealed containers due to the deleterious effect ofsuch oxygen on the flavor and physical stability of the beer. Recently,several types of oxygen analyzers have been evaluated by the brewingindustry for measurement of dissolved oxygen in beer. Most of theseinstruments are geared toward the measurement of dissolved oxygen inprocess streams and not in a packaged product. Two of these instrumentsare the Beckman Oxygen Analyzer and the Hays Oxygen Meter. The Haysinstrument is a portable unit and is designed for spot checking beer inprocess. This analyzer has good sensitivity and can detect and measureoxygen in parts per billion level. However, the method iselectrochemical and the electrodes necessary for the process are exposedto the beer medium; as a result, they are easily poisoned or corrodedand require frequent cleaning and replacement.

The Beckman Oxygen Analyzer is adaptable for monitoring dissolved oxygenin process streams, but its sensitivity leaves much to be desired.Again, the readings obtained with this instrument are normally only anapproximation of the dissolved oxygen content in process beer.

Such laboratory. models as are commercially available for theexamination of packaged beer normally require that the containersclosure be physically removed and the contents either measured in thecontainer or transferred to a different vessel for measurement of theoxygen content. This procedure presents obvious seriousproblems sincetransfer introduces the possibility of contamination by atmosphericoxygen. Furthermore, these instruments are not sufficiently sensitivefor measuring the trace amounts of oxygen normally found in beer. Thetypical measurement range on most of these instruments is 0-5 percentoxygen on the most sensitive setting. Presently,,there are no commercialinstruments available for measuring dissolved carbon dioxide, dissolvedoxygen and headspace oxygen in a single sealed container.

SUMMARY OF THE INVENTION The present invention takes advantage of thefact that devices are commercially available for measuring tracequantities of oxygen in a gas stream and for piercing the top of acontainer with a hollow needle under conditions such that there is norisk of loss of gas or of inleakage of oxygen. Using a special S-portedvalve having a central port which can be connected selectively to anyone of the other four ports, one of which four ports is sealed, it ispossible to draw samples of headspace gas or a liquid from a containersealed except for having been pierced by said piercing device and totransfer said known volumes to an inert gas stream. The apparatus isadapted for achieving equilibration of gas and liquid phases in a sealedcontainer. Where the sample withdrawn is liquid, the gas stream firsttransfers the liquid to a gas scrubber which retains the liquid whilepermitting oxygen, CO and trace volatile organic components to beflushed therefrom by means of said gas stream and carried into a carbondioxide absorber which removes carbon dioxide and other acidiccomponents from said gas stream. The gas stream then flows through anactivated carbon filter which removes traces of organic components. Thegas stream is then carried to the oxygen detector, a device which givesa signal porportional to the instantaneous oxygen content of the gasstream. The signal is recorded and integration of the area under thecurve gives the total 0 quantity.

When the tip of the sample probe is positioned in the headspace, thesyringe can draw a known volume of headspace gas from the container, andthe gas can be transferred to the inert gas stream to pass in turnthrough the gas scrubber, the carbon dioxide absorber and the carbonfilter to the oxygen detector for determining oxygen in a known volumeof headspace gas.

A gauge of a suitable range is connected to the probe for determiningthe total gas pressure in the system. As is evident, for high COcontents the total gas pressure and the CO pressure are essentiallyidentical.

Combination of the data thus obtained with measurements of the volume ofliquid and internal volume of the container makes it possible tocalculate the content of carbon dioxide. The process is carried out withthe container and the contents thereof at a known temperature,preferably 25C. Tables are available which give the quantity ofdissolved carbon dioxide as a function of the gauge pressure reading andmeasured temperature.

The procedure is rapid and can he carried out by relatively unskilledtechnicians.

The procedure and apparatus are also suitable for determining dissolvedoxygen in liquids in open containers, although no piercing of acontainer is required and the equilibration steps are omitted.

Accordingly, it is an object of the present invention to provide anapparatus for the determination of dissolved carbon dioxide anddissolved oxygen and headspace oxygen in a sealed container.

Another object of the present invention is to provide an apparatus'forthe determination of carbon dioxide and dissolved oxygen'and headspaceoxygen in a sealed container with high precision.

-A further object of the present invention is to provide an apparatusfor the determination of dissolved carbon dioxide and oxygen andheadspace oxygen in a sealed container which can be carried out rapidlyand by relatively unskilled technicians.

Still a further object of the present invention is to provide a methodand apparatus for determining dissolved carbon dioxide and dissolvedoxygen in process streams.

Yet a further object is to provide an apparatus for determiningdissolved oxygen in an open container.

An important object is to provide a method of determining dissolvedcarbon dioxide, dissolved oxygen and headspace oxygen in sealedcontainers, and dissolved oxygen in a liquid in an open container withhigh precision.

Still other objects and advantages of the invention will in part beobvious and will in part be apparent from the specification.

The invention accordingly comprises the several steps and the relationof one or more of such steps with respect to each of the others, and theapparatus embodying features of construction, combination of elementsand arrangement of parts which are adapted to effect such steps, all asexemplified in the following detailed disclosure, and the scope of theinvention willbe indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 5 is a graph showingoxygen-detector response as a function of known oxygen content in aninert gas stream.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A piercing device used forwithdrawing samples from a sealed container is shown in front and sideviews in FIGS. 3 and 4. The device is a modified form of the Zahm modelD-T piercing device manufactured by Zahm and Nagel Company,Incorporated, 74 Jewett Ave., Buffalo. NY. A container A shown as acapped.

bottle, but which also may be a sealed can, stands on a base B betweenupright rods 1. A movable cross bar C holds the container A firmly inposition by means of rubber gasket 11. Entry through the cover 13 ofcontainer A is effected by means of piercing needle 14. Piercing needle14 is hollow; probe 5 is positioned so that its lower end 15 is locatedproximate the tip of piercing needle 14. Probe 5 enters piercing needle14 through septum 6 held in one-eighth inch Swage-Lok nut available fromCrawford Fitting Company, Salem, Ohio. Probe 5 slides through the septum6 as held in nut 16 without entry of air or loss of gas. This slidingmotion is needed so that tip 15 can be positioned either in theheadspace in the container or in the liquid in the container.

Other components of the sampling device are pressure gauge 2 which ismounted directly above the piercing needle, and a micro 5-portdistribution valve 3 which is attached to the piercing device. Thedistribution valve is a Hamilton chemically inert, 5 4-way distribution,model D4 TTTTTXP, one-sixteenth inch OD tubing, Hamilton Company,Whittier, Calif. The sampling probe is stainless steel one-sixteenthinch O.D. tubing available from Analabs Inc., North Haven, Conn. Theseptum 6 is a gas chromatography silicone rubber septum cut to fitinside the one-eighth inch Swage-Lok nut, and is available from AppliedScience Laboratory, PO. Box 440, State College, Pa.

A gas-tight syringe 4 is connected to valve 3 at its central port 17.Syringe 4 is held firmly by clamp 18 to upright rod 19. Movement of theprobe 5 in a vertical direction is effected by sliding clamp 18 on rod19.

Central port 17 connects with an axial passage in the plug of valve 3.The plug of valve 3 also has therein a radial passage making connectionwith the axial passage. Rotation of the plug by means of handle 12 makesit possible to connect syringe 4 with any one of ports 21, 22, 23, or 24(see FIG. 1). Port 24 is sealed with a cap, thus affording an offposition to the valve. Port 21 has connected thereto a branched tubeshown in FIGS. 3 and 4 as a T-tube 7. Inert gas, such as nitrogen, ispassed through branched tube 7 and is used to transport sampleswithdrawn from container A to downstream separation and analyticalapparatus. Port 22 (FIG. 1) is connected to a source 38 of gascontaining a known quantity of oxygen which is used in calibrating andtesting the apparatus.

The volume of the measuring device 4, i.e., gas-tight syringe, should bechosen according to the oxygen content of the sample. For lowconcentrations of oxygen a large volume is necessary; conversely,samples having a high concentration of oxygen require a much smallervolume measuring device. For example, a three milliliter syringe is veryadequate for measuring beer samples. Air-saturated water samples high inoxygen concentration can best be measured with a syringe of less than1.0 milliliter volume.

Upstream of the valve 3 is a pressurized tank 26 of inert gas fittedwith an ON-OFF valve 27 which leads to a regulator 28, a flow meter 29,and an oxygen trap 44 which removes traces of oxygen from the carriergas stream. It is constructed from a stainless steel tube onefourth inchdiameter and 12 inches long, filled with Ridox oxygen scavenger. Ridoxis available from Fisher Scientific Co., Fairlawn, NJ. These componentssupply a constant stream of oxygen-free inert gas to arm 9 of branchedtube 7. The gas flowing through the branched tube 7 exits through arm 8which leads the gas into gas scrubber 31. Scrubbing unit 31 ispreferably a cylindrical glass vessel and may have a volume of about 30milliliters. A coarse porosity fritted glass disc 48 is positioned atthe end of inlet tube 32 to disperse the inert carrier gas and itscontents into very fine bubbles for removing dissolved gases from liquidsamples. Gas scrubber 31 is fitted with a drain line 33 for drainage ofliquid samples transferred from container A. The

milliliter test tube. lnert gas carrying any oxygen present leavesscrubber 34 through outlet tube 36. Traces of organic compounds whichmay be present in the gas stream are removed by activated carbon filter45. The gas stream then enters a standard Hersch Cell 37 whichdetermines the oxygen content of the gas electrochemically. The HerschCell is available from Paul Hersch, 910 Franklin Ter., Minneapolis,Minn. Any recorder having a l millivolt input such as the Beckman model100500 C l-lnch Potentiometric Recorder (not shown) can be used. Thisrecorder is available from Beckman instruments, Inc. Incorporated ofFullerton, Calif.

For calibration of the device a tank 38 of pressurized gas containing aknown fraction of oxygen supplies calibrating gas through valve 39 andregulator 41 at a known pressure to port 22 of micro-valve 3.

Alternatively, a known volume of oxygen can be inserted into inert gasstream leaving arm 8 by means of a microsyringe put through a rubberseptum 47 (preferably of silicone rubber) capping T-tube 46.

Analysis of the contents of a sealed container starts with attemperationof the container and its contents to a known constant temperature,preferably 25C. This may be effected by holding the container in a waterbath for a long enough period. The cover of the container is to bepierced with piercing device 14 as indicated schematically in FIG. 2.Here the rubber gasket 11 is shown schematically as a rubber sleeve 42.Similarly, silicone rubber septum 6 is shown schematically as a secondrubber sleeve 43. As is evident from FIG. 2, pressure gauge 2 isdirectly connected with piercing needle 14.

As the next step in the analysis, probe is flushed with carrier nitrogengas just prior to piercing the surface of the container by connectingport 21 with syringe 4. Carrier gas is drawn into the syringe andexpelled through probe 5 by connecting port 23 with syringe 4. Theprocedure is repeated three or four times to insure removal of entrappedoxygen in probe 5. Immediately following, the surface of the containeris pierced and probe 5 is lowered into the liquid in container A. Byconnecting port 23 with syringe 4, a sample may be drawn up into syringe4. The plunger of syringe 4 is pumped out and in until the reading ongauge 2 is constant after each expulsion of sample from syringe 4. Thereading on gauge 2 is then noted as the total gas pressure over thecarbonated liquid. The purpose of the pumping action is to obtainequilibrium between the liquid and gas phase and to make certain that ahomogeneous sample is taken. Generally, from two to five strokes arenecessary. After taking the reading of gauge 2, a sample of theequilibrated liquid is drawn through port 23 into syringe 4, stop-cock 3having been rotated to connect central port 17 with port 23.Equilibration can also be achieved by shaking the container or the waterbath, either mechanically or by ultrasonic vibrator (not shown).

Syringe 4 is then connected to port 21 by rotation of handle 12. Thesample in syringe 4 is injected into the inert gas stream coming fromtank 26 through valve 27, regulator 28, flow meter 29 and O trap 44 intobranched tube 7. The gas stream, containing injected liquid samplepasses through tubing 32 into scrubber 31 containing water. The gasstream continues to flow after the transfer of the sample into scrubber31 is complete and serves to sweep out all traces of CO 0 and volatileorganic components. I These gases then pass into absorber 34 whichremoves'CO from the gas stream and thence to carbon filter 45 whichremoves volatile organic components from the gas stream. For effectivescrubbing and absorption, the tubes leading into scrubber 31 andabsorber 34 preferably have coarse porosity fritted glass discs.positioned at the end of each of the inlet tubes to disperse the inertcarrier gas into small bubbles. Scrubber 31 is fitted with a stopcock 33for drainage of the liquid sample after the analysis is complete.

The gas stream, now containing only oxygen, passes through tube 36 intooxygen detector 37 in which the oxygen content is determinedelectrochemically.

After determining the oxygen content of the liquid phase, probe 5 israised so that its tip 15 is in the headspace of the container. A sampleis taken as described above, injected into the gas stream through port21 after which the oxygen detector 37 determines the total quantity ofoxygen in the sample taken.

Periodically, the performance of the equipment is checked by taking asample of gas containing a known quantity of oxygen from pressurizedtank 38 through valve 39, regulator 41 and port 22. Syringe 4 isutilized to accept a sample of gas of known volume and pres sure and thesample is then transferred into the inert gas stream from pressurizedtank 26 in the usual manner. A low reading would indicate either thatoxygen is being lost in the transfer from port 22 to the inert gasstream or that the Hersch cell is not operating properly. Conversely, ahigh reading would indicate that air is entering the system as, forinstance, in the piercing of the container, or again, that the Herschcell is operating improperly. I

A particular advantage of the system described herein is that thesyringe may be matched to the expected oxygen content of the sample tobe analyzed. In this way, maximum accuracy in the measurement of thevolume of the sample can be achieved. For instance, for beer headspace,normally a 0.20 ml sample is sufficient. For beer itself, sample volumesof from 0.50 to 2.00 ml are necessary.

Oxygen in the inert gas stream is reduced electrochemically in theHersch cell, and the resultant current is proportional to the oxygencontent of the sample. This current is measured by a recording devicesuch as a millivolt strip chart recorder. A 10 ohm resistance decade boxwith a selection switch is conveniently set across the terminals of theHersch cell. The millivolt strip chart recorder preferably has a spanranging from I to millivolts. The selector switch on the resistancedecade box can be set for any value of resistance from 1 to 10 ohmsdepending on the current produced by the cell and the amount of responserequired on the strip chart recorder. Likewise, the recorders millivoltspan range can be selected in accordance with the oxygen content of thegas stream and the size of the signal desired. For example, in beeranalysis. a 5 ohm resistor setting on the resistor decade box and amillivolt span range setting of l millivolt on the strip chart recorderproduces a very acceptable signal on the recorder chart paper. Forair-saturated water or atmospheric air where the oxygen concentrationsare quite high, a setting on the resistance decade box of 1 ohm and lmillivolt on the strip chart recorder are appropriate. FIG. 5 shows theresponse of the detector as a function of content in the stream.

Following are Tables showing test results which clearly show theexcellent reproducibility of analyses achieved by the disclosedapparatus and process.

TABLE I Reproducibility of Dissolved Oxygen Values 1 In Beer (OneSample) Replicate Nov Dissolved Oxygen (ppm) 1 0.22 2 0.22 3 0.23 4 0.235 0.23 6 0,23 7 0.24 8 0.24 9 0.24 Mean 0.23 Std. Dev. 0.0l3 Rel. Std.Dev. 5.65

Note: All analyses run on a single bottle of beer TABLE IIReproducibility of Gaseous Oxygen Values (From Commercial CylinderNitrogen) Replicate No. Oxygen (ppm) l 4.20 2 4.30 3 4.30 4 4.30 5 4.306 4.20 Mean 4.30 Std. Dev. 0.063 Rel. Std. Dev. 1.47

TABLE III Analysis of Beer Samples for Carbon Dioxide and OxygenAnalysis of Aerated Wort Samples for Dissolved Oxygen vSample DissolvedOxygen (ppm) TABLE lV-Continued Analysis of Aerated Wort Samples forDissolved Oxygen Sample Dissolved Oxygen (ppm) It should be noted thatthe apparatus and method can with suitable and obvious modification beused for the detection of dissolved oxygen in liquids in opencontainers. The probe is inserted into the liquid as previouslydescribed, and a sample is withdrawn by the sy ringe and thentransferred to the inert gas stream. No equilibration of gas and liquidphases by filling and emptying the syringe is needed.

As aforenoted, to standardize the apparatus a T-tube connection 46 iscovered with a silicone rubber septum 47 through which a known quantityof oxygen can be inserted from a microliter hypodermic syringe. FIG. 5shows the results obtained. The circles in FIG. 5 were obtained usingthe method described as used on beer samples. The crosses representmeasurements of dissolved O in water specimens. (0 in water determinedby Winkler method.)

It will thus be seen that the objects set forth above, among those madeapparent from the preceding description, are efficiently attained, andsince certain changes may be made in carrying out the above method andin the construction set forth without departing from the spirit andscope of the invention, it is intended that all matter contained in theabove description and 'shown in the accompanying drawings shall beinterpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed and all statements of the scope of the invention which, as amatter of language, might be said to fall therebetween.

What is claimed is:

1. An apparatus for determining dissolved O and CO in a liquid in acontainer and O in the headspace of said container, wherein saidapparatus includes a source of inert gas for providing a stream of gasat a chosen rate, a pressure gauge for measuring total gas pressure insaid container, hollow tubular piercing means for penetrating acontainer without loss or inleakage of gas at the region of penetration,said piercing means having a sharp tip, the tip of said piercing meansbeing selectively positionable in the headspace or in the liquid afterpiercing said container, said pressure gauge being operatively connectedwith said piercing means, means for removing CO and volatile organiccomponents from a gas stream, and means for measuring the oxygen contentof said gas stream, wherein said improvement comprises: valve meanshaving first, second and third ports and an off position, and connectingmeans for connecting said first port to any of said second and thirdports and said off position, a syringe detachably connected to saidfirst port, a hollow probe tube lying within said hollow piercing meansand having two ends, one of the ends of said hollow probe tube beingproximate the tip of said piercing means and the other of its ends beingconnected to said second port of said valve means; and a branched tubehaving three ports, the first of said tube ports being connected to saidthird valve port, the second of said tube ports being connected to saidsource of inert gas and the third of said tube ports being connected tosaid means for removing CO and volatile organic components from said gasstream and to said oxygen-content measuring means for introduction of asample taken by said syringe and from said syringe into said gas streamand flow in sequence through said means for removing CO and volatileorganic components and oxygencontent measuring means, thereby making itpossible to determine the oxygen content of said sample, the CO contentof said sample being determinable from the reading of said pressuregauge.

2. An apparatus as defined in claim 1, wherein said inert gas source isa container of nitrogen, and further comprising means for controllinggas flow from said nitrogen container at a constant, selected rate.

3. An apparatus as defined in claim 1, further comprising a scrubber forreceiving a quantity of liquid drawn from said container by said syringeand injected into said gas stream, said scrubber having a disperser forbreaking said gas stream into fine bubbles to facilitate removal ofdissolved gases from said liquid.

4. An apparatus as defined in claim 1, further comprising a T'tubeconnected between said valve means and said oxygen-content measuringmeans for transmitting said inert gas stream therebetween, said T-tubehaving a port covered with a rubber septum for introduction of a knownquantity of oxygen from a microsyringe into said inert gas stream forthe purpose of calibrating said oxygen-content measuring means.

5. An apparatus as defined in claim 1, further comprising a fourth porton said valve means, said fourth port being connectable to said firstport, and a source of gas with a known oxygen content connected to saidfourth port.

6. An apparatus as defined in claim 5, wherein said gas source is acontainer of nitrogen having a known oxygen content, said gas sourcebeing intended for use in calibrating said apparatus.

7. A method of determining O and CO in a liquid in a container and O inthe headspace of said container by means of apparatus including a hollowpiercing needle, said needle having a tip the position of which isvertically adjustable, a hollow probe within said needle and essentiallyconcentric therewith, said probe having one end proximate the tip ofsaid piercing needle, a pressure gauge for reading total gas pressureconnected to said piercing needle, valve means having first, sec nd andthird ports and an off position, a syringe connected to said first port,the other end of said hollow probe being connected to said second port,a branched tube having three tube ports one of which is connected tosaid third valve means port, a second of said tube ports being connectedto an oxygen-free gas source and the third of said tube ports beingconnected to a train comprising sequentially a gas scrubber, a C0absorber, an activated carbon filter and an oxygencontent measuringmeans, said method comprising the steps of attemperating said containerand the contents thereof, drawing a volume of inert gas into saidsyringe, expelling said volume of inert gas through said probe to flushany oxygen out of same, piercing said container and positioning the tipof said probe in said liquid, drawing a sample of liquid into saidsyringe and returning said liquid to said container a sufficient numberof times to ensure equilibration of liquid and gas phases, said removaland return of liquid being continued until a constant reading isobserved on said gas pressure gauge when all liquid is returned and saidvalve means is placed in said off position, noting said constantreading, drawing a known volume ofliquid into said syringe, expellingsaid known volume of liquid through said branched tube into a stream ofinert gas for transfer into said gas scrubber which retains said liquidwhile said inert-gas stream carries CO and 0 into said CO absorber andcarbon filter and said 0 thence into said oxygen-content measuring meansfor determining the quantity of O in said known volume of liquid,raising said probe into said headspace in said container, drawing arepresentative known volume of headspace gas into said syringe, andexpelling said known volume of headspace gas into said gas stream forpassage through said gas scrubber, CO absorber, and carbon filter andthence to said oxygen-content measuring means for determining the 0content of said known volume headspace gas, all transfers to and fromsaid syringe to and from selected ports being carried out bymanipulation of said valve means, the combination of the data thusobtained with the measured volume of said liquid and the measured volumeof said container making it possible to determine the CO and 0 contentof said liquid and the 0 content of said headspace.

8. The method as defined in claim 7, wherein said valve means has afourth port connectable to said first port and further comprising thestep of passing a known volume of a gas having a known content of 0through said apparatus by means of said fourth valve-means port to testand calibrate said apparatus.

9. A method of determining the dissolved 0 content in a liquid in anopen container comprising the steps of inserting a hollow probe intosaid liquid, said probe being connected to a first side port of amulti-ported valve means having a central port, connecting the centralport of said valve means to said first side port, drawing a sample ofknown volume into a syringe connected to said central port, connectingsaid central port to a second side port, said second side port beingconnected in turn to a T-tube through which a stream of inert gas isflowing in sequence through a gas scrubber, a C0 absorber and anactivated carbon filter to an oxygen-content determining means, andinjecting the contents of said syringe into said gas stream through saidsecond side port and said T-tube, whereby the O in said sample iscarried to said oxygen-content determining means for determining thequantity of dissolved 02a UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION Patent No. 3,849,070 Dated November 19, 1974 Inventor(s) AlanC. Garza & Vincent S. Bavisotto It is certified that error appears inthe above-identified patent and that said Letters Patent are herebycorrected as shown below:

On the cover page, the Assignee should read -Theodore Hamm Company, St.Paul, Minnesota--.

Signed and sealed this 29th day of April 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Conmissioner of Patents Attesting Officerand Trademarks P0405 ($59, uscoMM-Dc 60376-P69 U-SI GOVIINNINT PRINTINGOFFICE: 0-306-334,

1. AN APPARATUS FOR DETERMINING DISSOLVED O2 AND CO2 IN A LIQUID IN ACONTAINER AND O2 IN THE HEADSPACE OF SAID CONTAINER WHEREIN SAIDAPPARATUS INCLUDES A SOURCE OF INERT GAS FOR PROVIDING A STREAM OF GASAT A CHOSEN RATE, A PRESSURE GAUGE FOR MEASURING TOTAL GAS PRESSURE INSAID CONTAINER, HOLLOW TUBULAR PIERCING MEANS FOR PENETRATING ACONTAINER WITHOUT LOSS OR INLEAKAGE OF GAS AT THE REGION OF PENETRATION,SAID PIERCING MEANS HAVING A SHARP TIP, THE TIP OF SAID PIERCING MEANSBEING SELECTIVELY POSITIONABLE IN THE HEADSPACE OR IN THE LIQUID AFTERPIERCING SAID CONTAINER, SAID PRESSURE GAUGE BEING OPERATIVELY CONNECTEDWITH SAID PIERCING MEANS, MEAN FOR REMOVING CO2 AND VOLATILE ORGANICCOMPONENTS FROM A GAS STREAM, AND MEANS FOR MEASURING THE OXYGEN CONTENTOF SAID GAS STREAM, WHEREIN SAID IMPROVEMENT COMPRISES: VALVE MEANSHAVING FIRST, SECOND AND THIRD PORTS AND AN OFF POSITION, AND CONNECTINGMEANS FOR CONNECTING SAID FIRST PORT TO ANY OF SAID SECOND AND THIRDPORTS AND SAID OFF POSITION, A SYRINGE DETACHABLY CONNECTED TO SAIDFIRST PORT, A HOLLOW PROBE TUBE LYING WITHIN SAID HOLLOW PIERCING MEANSAND HAVING TWO ENDS, ONE OF THE ENDS OF SAID HOLLOW PROBE TUBE BEINGPROXIMATE THE TIP OF SAID PIERCING MEANS AND THE OTHER OF ITS ENDS BEINGCONNECTED TO SAID SECOND PORT OF SAID VALVE MEANS; AND A BRANCHED TUBEHAVING THREE PORTS, THE FIRST OF SAID TUBE PORTS BEING CONNECTED TO SAIDTHIRD VALVE PORT, THE SECOND OF SAID TUBE PORTS BEING CONNECTED TO SAIDSOURCE OF INERT GAS AND THE THIRD OF SAID TUBE PORTS BEING CONNECTED TOSAID MEANS FOR REMOVING CO2 AND VOLATILE ORGANIC COMPONENTS FROM SAIDGAS STREAM AND TO SAID OXYGEN-CONTENT MEASURING MEANS FOR INTRODUCTIONOF A SAMPLE TAKEN BY SAID SYRINGE AND FROM SAID SYRINGE INTO SAID GASSTREAM AND FLOW IN SEQUENCE THROUGH SAID MEANS FOR REMOVING CO2 ANDVOLATILE ORGANIC COMPONENTS AND OXYGEN-CONTENT MEASURING MEANS, THEREBYMAKING IT POSSIBLE TO DETERMINED THE OXYGEN CONTENT OF SAID SAMPLE, THECO2 CONTENT OF SAID SAMPLE BEING DETERMINABLE FROM THE READING OF SAIDPRESSURE GAUGE.
 2. An apparatus as defined in claim 1, wherein saidinert gas source is a container of nitrogen, and further comprisingmeans for controlling gas flow from said nitrogen container at aconstant, selected rate.
 3. An apparatus as defined in claim 1, furthercomprising a scrubber for receiving a quantity of liquid drawn from saidcontainer by said syringe and injected into said gas stream, saidscrubber having a disperser for breaking said gas stream into finebubbles to facilitate removal of dissolved gases from said liquid.
 4. Anapparatus as defined in claim 1, further comprising a T-tube connectedbetween said valve means and said oxygen-content measuring means fortransmitting said inert gas stream therebetween, said T-tube having aport covered with a rubber septum for introduction of a known quantityof oxygen from a micro-syringe into said inert gas stream for thepurpose of calibrating said oxygen-content measuring means.
 5. Anapparatus as defined in claim 1, further comprising a fourth port onsaid valve means, said fourth port being connectable to said first port,and a source of gas with a known oxygen content connected to said fourthport.
 6. An apparatus as defined in claim 5, wherein said gas source isa container of nitrogen having a known oxygen content, said gas sourcebeing intended for use in calibrating said apparatus.
 7. A method ofdetermining O2 and CO2 in a liquid in a container and O2 in theheadspace of said container by means of apparatus including a hollowpiercing needle, said needle having a tip the position of which isvertically adjustable, a hollow probe within said needle and essentiallyconcentric therewith, said probe having one end proximate the tip ofsaid piercing needle, a pressure gauge for reading total gas pressureconnected to said piercing needle, valve means having first, second andthird ports and an off position, a syringe connected to said first port,the other end of said hollow probe being connected to said second port,a branched tube having three tube ports one of which is connected tosaid third valve means port, a second of said tube ports being connectedto an oxygen-free gas source and the third of said tube ports beingconnected to a train comprising sequentially a gas scrubber, a CO2absorber, an activated carbon filter and an oxygen-content measuringmeans, said method comprising the steps of attemperating said containerand the contents thereof, drawing a volume of inert gas into saidsyringe, expelling said volume of inert gas through said probe to flushany oxygen out of same, piercing said container and positioning the tipof said probe in said liquid, drawing a sample of liquid into saidsyringe and returning said liquid to said container a sufficient numberof times to ensure equilibration of liquid and gas phases, said removaland return of liquid being continued until a constant reading isobserved on said gas pressure gauge when all liquid is returned and saidvalve means is placed in said off position, noting said constantreading, drawing a known volume of liquid into said syringe, expellingsaid known volume of liquid through said branched tube into a stream ofinert gas for transfer into said gas scrubber which retains said liquidwhile said inert-gas stream carries CO2 and O2 into said CO2 absorberand carbon filter and said O2 thence into said oxygen-content measuringmeans for determining the quantity of O2 in said known volume of liquid,raising said probe into said headspace in said container, drawing arepresentative known volume of headspace gas into said syringe, andexpelling said known volume of headspace gas into said gas stream forpassage through said gas scrubber, CO2 absorber, and carbon filter andthence to said oxygen-content measuring means for determining the O2content of said known volume head-space gas, all transfers to and fromsaid Syringe to and from selected ports being carried out bymanipulation of said valve means, the combination of the data thusobtained with the measured volume of said liquid and the measured volumeof said container making it possible to determine the CO2 and O2 contentof said liquid and the O2 content of said headspace.
 8. The method asdefined in claim 7, wherein said valve means has a fourth portconnectable to said first port and further comprising the step ofpassing a known volume of a gas having a known content of O2 throughsaid apparatus by means of said fourth valve-means port to test andcalibrate said apparatus.
 9. A method of determining the dissolved O2content in a liquid in an open container comprising the steps ofinserting a hollow probe into said liquid, said probe being connected toa first side port of a multi-ported valve means having a central port,connecting the central port of said valve means to said first side port,drawing a sample of known volume into a syringe connected to saidcentral port, connecting said central port to a second side port, saidsecond side port being connected in turn to a T-tube through which astream of inert gas is flowing in sequence through a gas scrubber, a CO2absorber and an activated carbon filter to an oxygen-content determiningmeans, and injecting the contents of said syringe into said gas streamthrough said second side port and said T-tube, whereby the O2 in saidsample is carried to said oxygen-content determining means fordetermining the quantity of dissolved O2.